Efficacy comparison of high-genetic barrier nucleos(t)ide analogues in treatment-naïve chronic hepatitis B patients: a network meta-analysis

Background/Aims@#Four high-genetic barrier nucleos(t)ide analogues (NAs) for chronic hepatitis B (CHB), namely entecavir (ETV), tenofovir disoproxil fumarate (TDF), tenofovir alafenamide (TAF), and besifovir dipivoxil maleate (BSV), have been established. The aim of this study is to investigate the efficacy of four high-genetic barrier NAs using a network meta-analysis of randomized trials and propensity score-matched cohorts. @*Methods@#Systematic search was performed using PubMed, Cochrane library, and EMBASE and included randomized controlled trials and cohort studies that used propensity score matching. Studies on treatment-naïve CHB patients treated with ETV, TDF, TAF, or BSV were included. Outcomes included alanine aminotransferase normalization and hepatitis B e antigen seroclearance at week 48 and undetectable hepatitis B virus DNA at weeks 48 and 96. Network meta-analysis was performed to synthesize the results. @*Results@#In total, 15,000 patients from 16 studies were included. In terms of 48- and 96-week virologic response (VR), TDF outperformed ETV with statistical significance (48 weeks: odds ratio [OR], 1.38; p < 0.001; 96 weeks: OR, 1.57; p = 0.004). ETV was ranked first for 48-week biochemical response (BR) and outperformed TDF (OR, 0.76; p = 0.028). In the sensitivity analyses, 48-week VR from randomized-controlled trials were compiled, and the same trend toward the superiority of TDF over ETV was found (OR, 1.51; p = 0.030). @*Conclusions@#Four high-genetic barrier NAs were compared, and TDF was more likely to achieve a VR after 48 weeks, while ETV provided a superior BR after 48 weeks.

Targetoid Primary Liver Malignancy in Chronic Liver Disease: Prediction of Postoperative Survival Using Preoperative MRI Findings and Clinical Factors

Objective@#We aimed to assess and validate the radiologic and clinical factors that were associated with recurrence and survival after curative surgery for heterogeneous targetoid primary liver malignancies in patients with chronic liver disease and to develop scoring systems for risk stratification. @*Materials and Methods@#This multicenter retrospective study included 197 consecutive patients with chronic liver disease who had a single targetoid primary liver malignancy (142 hepatocellular carcinomas, 37 cholangiocarcinomas, 17 combined hepatocellular carcinoma-cholangiocarcinomas, and one neuroendocrine carcinoma) identified on preoperative gadoxetic acid-enhanced MRI and subsequently surgically removed between 2010 and 2017. Of these, 120 patients constituted the development cohort, and 77 patients from separate institution served as an external validation cohort. Factors associated with recurrence-free survival (RFS) and overall survival (OS) were identified using a Cox proportional hazards analysis, and risk scores were developed. The discriminatory power of the risk scores in the external validation cohort was evaluated using the Harrell C-index. The Kaplan–Meier curves were used to estimate RFS and OS for the different risk-score groups. @*Results@#In RFS model 1, which eliminated features exclusively accessible on the hepatobiliary phase (HBP), tumor size of 2–5 cm or > 5 cm, and thin-rim arterial phase hyperenhancement (APHE) were included. In RFS model 2, tumors with a size of > 5 cm, tumor in vein (TIV), and HBP hypointense nodules without APHE were included. The OS model included a tumor size of > 5 cm, thin-rim APHE, TIV, and tumor vascular involvement other than TIV. The risk scores of the models showed good discriminatory performance in the external validation set (C-index, 0.62–0.76). The scoring system categorized the patients into three risk groups: favorable, intermediate, and poor, each with a distinct survival outcome (all log-rank p < 0.05). @*Conclusion@#Risk scores based on rim arterial enhancement pattern, tumor size, HBP findings, and radiologic vascular invasion status may help predict postoperative RFS and OS in patients with targetoid primary liver malignancies.

Anti-fibrotic effects of branched-chain amino acids on hepatic stellate cells

Background/Aims@#Patients with liver cirrhosis (LC) have low levels of branchedchain amino acids (BCAAs). There is accumulating evidence that BCAAs have anti- fibrotic effects in cirrhosis. This study is aimed to evaluate the effect of BCAAs on the function and phenotype of activated hepatic stellate cells (HSCs). @*Methods@#LX-2, an immortalized human stellate cell line, was used in in vitro experiments. LX-2 cells were exposed to transforming growth factor β1 (TGF-β1) and BCAAs or to valine, leucine, and isoleucine, which are components of BCAAs. Activation of the TGF-β signaling pathway in LX-2 cells was observed using real- time quantitative polymerase chain reaction and Western blotting. @*Results@#The increased expression of snail family transcriptional repressor 1 (SNAI1) was observed in LX-2 cells activated by TGF-β1. After BCAA treatment, its expression was significantly decreased at the mRNA level. The increased expression of Col1α1 and TIMP2 at the mRNA level and alpha smooth muscle actin at the protein level in activated LX-2 cells decreased after BCAA treatment. Among the BCAA components, leucine and valine significantly abrogated TGF-β-induced activation of LX-2 cells. BCAA treatment led to the decreased phosphorylation of Smad2 and p38 proteins, which are markers for Smad and Smad-independent p38 mitogen-activated protein kinase signaling pathways, respectively. @*Conclusions@#BCAA treatment can improve hepatic fibrosis by directly affecting the activated state of hepatic stellate cells through inhibition of the TGF-β signaling pathway. Among BCAA components, leucine and valine mainly abrogated TGF-β-induced activation of HSCs. Our results suggest that BCAA may be used to attenuate the progression of liver fibrosis.

Therapeutic mechanisms and beneficial effects of non-antidiabetic drugs in chronic liver diseases

The global burden of chronic liver disease (CLD) is substantial. Due to the limited indication of and accessibility to antiviral therapy in viral hepatitis and lack of effective pharmacological treatment in nonalcoholic fatty liver disease, the beneficial effects of antidiabetics and non–antidiabetics in clinical practice have been continuously investigated in patients with CLD. In this narrative review, we focused on non-antidiabetic drugs, including ursodeoxycholic acid, silymarin, dimethyl4,4’-dimethoxy-5,6,5’,6’-dimethylenedixoybiphenyl-2,2’-dicarboxylate, L-ornithine L-aspartate, branched chain amino acids, statin, probiotics, vitamin E, and aspirin, and summarized their beneficial effects in CLD. Based on the antioxidant, anti-inflammatory properties, and regulatory functions in glucose or lipid metabolism, several non–antidiabetic drugs have shown beneficial effects in improving liver histology, aminotransferase level, and metabolic parameters and reducing risks of hepatocellular carcinoma and mortality, without significant safety concerns, in patients with CLD. Although the effect as the centerpiece management in patients with CLD is not robust, the use of these non-antidiabetic drugs might be potentially beneficial as an adjuvant or combined treatment strategy.

Crosstalk between tumor-associated macrophages and neighboring cells in hepatocellular carcinoma

The tumor microenvironment generally shows a substantial immunosuppressive activity in hepatocellular carcinoma (HCC), accounting for the suboptimal efficacy of immune-based treatments for this difficult-to-treat cancer. The crosstalk between tumor cells and various cell types in the tumor microenvironment is strongly related to HCC progression and treatment resistance. Monocytes are recruited to the HCC tumor microenvironment by various factors and become tumor-associated macrophages (TAMs) with distinct phenotypes. TAMs often contribute to weakened tumor-specific immune responses and a more aggressive phenotype of malignancy. Recent single-cell RNA-sequencing data have demonstrated the central roles of specific TAMs in tumorigenesis and treatment resistance by their interactions with various cell populations in the HCC tumor microenvironment. This review focuses on the roles of TAMs and the crosstalk between TAMs and neighboring cell types in the HCC tumor microenvironment.

Diagnostic performance of serum exosomal miRNA-720 in hepatocellular carcinoma

Background@#/Aim: Hepatocellular carcinoma (HCC) is associated with poor prognosis, largely due to late detection. Highly accurate biomarkers are urgently needed to detect early-stage HCC. Our study aims to explore the diagnostic performance of serum exosomal microRNA (miR)-720 in HCC. @*Methods@#Exosomal miRNA was measured via quantitative real-time PCR. A correlation analysis of exosomal miR-720 and tumor or clinico-demographic data of patients with HCC was performed. The receiver operating characteristic (ROC) curve was used to assess the diagnostic capacity of serum exosomal miR-720 for HCC, in comparison with α-fetoprotein (AFP) and prothrombin induced by vitamin K absence or antagonist-II (PIVKA-II). @*Results@#MiR-720 was chosen as a potential HCC marker via miR microarray based on significant differential expression between tumor and non-tumor samples. Serum exosomal miR-720 was significantly upregulated in patients with HCC (n=114) versus other liver diseases (control, n=30), with a higher area under the ROC curve (AUC=0.931) than the other markers. Particularly, serum exosomal miR-720 showed superior performance in diagnosing small HCC (< 5 cm; AUC=0.930) compared with AFP (AUC=0.802) or PIVKA-II (AUC=0.718). Exosomal miR-720 levels showed marginal correlation with tumor size. The proportion of elevated miR-720 also increased with intrahepatic tumor stage progression. Unlike AFP or PIVKA-II showing a significant correlation with aminotransferase levels, the exosomal miR-720 level was not affected by aminotransferase levels. @*Conclusions@#Serum exosomal miR-720 is an excellent biomarker for the diagnosis of HCC, with better performance than AFP or PIVKA-II. Its diagnostic utility is maintained even in small HCC and is unaffected by aminotransferase levels.

Targeted Next-Generation Sequencing of Plasma CellFree DNA in Korean Patients with Hepatocellular Carcinoma

Background@#Hepatocellular carcinoma (HCC) is the second-most-common cause of cancer-related deaths worldwide, and an accurate and non-invasive biomarker for the early detection and monitoring of HCC is required. We assessed pathogenic variants of HCC driver genes in cell-free DNA (cfDNA) from HCC patients who had not undergone systemic therapy. @*Methods@#Plasma cfDNA was collected from 20 HCC patients, and deep sequencing was performed using a customized cfDNA next-generation sequencing panel, targeting the major HCC driver genes (TP53, CTNNB1, TERT) that incorporates molecular barcoding. @*Results@#In 13/20 (65%) patients, we identified at least one pathogenic variant of two major HCC driver genes (TP53 and CTNNB1), including 16 variants of TP53 and nine variants of CTNNB1. The TP53 and CTNNB1 variants showed low allele frequencies, with median values of 0.17% (range: 0.06%–6.99%) and 0.07% (range: 0.05%–0.96%), respectively. However, the molecular coverage of variants was sufficient, with median values of 5,543 (range: 2,317–9,088) and 7,568 (range: 2,400–9,633) for TP53 and CTNNB1 variants, respectively. @*Conclusions@#Our targeted DNA sequencing successfully identified low-frequency pathogenic variants in the cfDNA from HCC patients by achieving high coverage of unique molecular families. Our results support the utility of cfDNA analysis to identify somatic gene variants in HCC patients.

Persistence of intrahepatic hepatitis B virus DNA integration in patients developing hepatocellular carcinoma after hepatitis B surface antigen seroclearance

Background/Aims@#The role of hepatitis B virus (HBV) integration into the host genome in hepatocarcinogenesis following hepatitis B surface antigen (HBsAg) seroclearance remains unknown. Our study aimed to investigate and characterize HBV integration events in chronic hepatitis B (CHB) patients who developed hepatocellular carcinoma (HCC) after HBsAg seroclearance. @*Methods@#Using probe-based HBV capturing followed by next-generation sequencing technology, HBV integration was examined in 10 samples (seven tumors and three non-tumor tissues) from seven chronic carriers who developed HCC after HBsAg loss. Genomic locations and patterns of HBV integration were investigated. @*Results@#HBV integration was observed in six patients (85.7%) and eight (80.0%) of 10 tested samples. HBV integration breakpoints were detected in all of the non-tumor (3/3, 100%) and five of the seven (71.4%) tumor samples, with an average number of breakpoints of 4.00 and 2.43, respectively. Despite the lower total number of tumoral integration breakpoints, HBV integration sites in the tumors were more enriched within the genic area. In contrast, non-tumor tissues more often showed intergenic integration. Regarding functions of the affected genes, tumoral genes with HBV integration were mostly associated with carcinogenesis. At enrollment, patients who did not remain under regular HCC surveillance after HBsAg seroclearance had a large HCC, while those on regular surveillance had a small HCC. @*Conclusions@#The biological functions of HBV integration are almost comparable between HBsAg-positive and HBsAgserocleared HCCs, with continuing pro-oncogenic effects of HBV integration. Thus, ongoing HCC surveillance and clinical management should continue even after HBsAg seroclearance in patients with CHB.

Successful Sequential Therapy Involving Regorafenib after Failure of Sorafenib in a Patient with Recurrent Hepatocellular Carcinoma after Liver Transplantation

The efficacy and safety of sequential systemic therapy for the treatment of recurrent hepatocellular carcinoma (HCC) after liver transplantation (LT) are not well established. This study describes a successful experience where sequential therapy with sorafenib followed by regorafenib was used to treat recurrent HCC in a 54-year old male LT recipient. After HCC recurred in both lungs 10 months after LT, sorafenib was administered with radiation therapy to treat pulmonary metastases. However, after 4 months of sorafenib treatment showed progressive pulmonary metastases, sequential regorafenib treatment was started. After 3 months (cycles) of regorafenib treatment, tumor response was partial, and after 6 months (cycles), disease status remained stable without signs of progression or drug-related serious adverse events. This case suggests that sequential systemic therapy is feasible in patient with recurrent HCC after LT.

Infiltration of T Cells and Programmed Cell Death Ligand 1-expressing Macrophages as a Potential Predictor of Lenvatinib Response in Hepatocellular Carcinoma

Background/Aims@#Lenvatinib was recently proven to be non-inferior to sorafenib in treating unresectable hepatocellular carcinoma (HCC) in a phase-3 randomized controlled trial. In this study, we investigated whether the response to lenvatinib was affected by tumor immunogenicity. @*Methods@#Between May 2019 and April 2020, nine patients with intermediate-to-advanced HCC, who were treated with lenvatinib after liver biopsy, were enrolled. Immunohistochemical staining and multi-color flow cytometry were performed on specimens obtained from liver biopsy. @*Results@#Among the nine patients enrolled, four showed objective responses (complete responses+partial responses). Immunohistochemical staining for CD3, CD68, and programmed cell death ligand 1 (PD-L1) demonstrated that patients with objective responses showed marked infiltration of T cells and PD-L1-expressing macrophages in intra-tumoral and peri-tumoral tissues compared to those without objective responses. A significant difference in the numbers of infiltrated T cells, both in the intra-tumoral (P<0.01) and peri-tumoral regions (P<0.05), were identified between responders and non-responders. Regarding the number of infiltrated macrophages, no significant difference was found between the responders and non-responders, although the number of PD-L1-expressing tumor-associated macrophages was significantly higher in responders than that in non-responders (P<0.05). @*Conclusions@#Tumor immunogenicity, as indicated by T cell and PD-L1-positive macrophage infiltration, affects lenvatinib response in unresectable HCC.

Liver Transplantation after Successful Downstaging with Hepatic Arterial Infusion Chemotherapy in a Patient with Hepatocellular Carcinoma with Portal Vein Tumor Thrombus

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. The majority of patients with HCC are diagnosed at advanced disease stages with vascular invasion, where curative approaches are often not feasible. Currently, sorafenib is the only available standard therapy for HCC with portal vein tumor thrombosis (PVTT). However, in many cases, sorafenib therapy fails to achieve satisfactory results in clinical practice. We present a case of advanced HCC with PVTT that was treated with hepatic arterial infusion chemotherapy (HAIC) followed by liver transplantation. Three cycles of HAIC treatment resulted in necrotic changes in most of the tumors, and PVTT was reduced to an extent at which liver transplantation was possible. Further studies are required to determine the treatment strategies for advanced HCC with PVTT that can improve prognosis.

Early Onset Polymorphic Post-transplant Lymphoproliferative Disease Mimicking a Solitary Necrotizing Abscess in a Graft Liver

Although post-transplantation lymphoproliferative disease (PTLD) after liver transplantation is very rare, its prognosis is worse than that of PTLD following other types of solid organ transplantation. Here, we report a rare case of early onset polymorphic PTLD in a graft liver occurring five months after deceased-donor liver transplantation due to hepatocellular carcinoma and hepatitis C virus infection. Initially, findings from contrast-enhanced magnetic resonance imaging mistakenly suspected the lesion was a necrotizing abscess with central necrosis. However, ¹⁸F-fluorodeoxyglucose positron emission tomography and biopsy findings confirmed an Epstein-Barr virus (EBV)-associated, B cell type polymorphic PTLD with central necrosis. Our case suggests regular monitoring of EBV serologic status for liver transplant recipients who were initially in an EBV seronegative state. Although early-onset PTLD is very rare after liver transplantation, PTLD should be suspected when recipients show the seroconversion for EBV proteins and the development of new tumors with various clinical presentations.

Effect of antiviral therapy in reducing perinatal transmission of hepatitis B virus and maternal outcomes after discontinuing them

BACKGROUND/AIMS: There have been numerous efforts to reduce mother-to-child transmission (MTCT) of hepatitis B virus (HBV) with antiviral agents during pregnancy. However, there are limited data regarding the outcomes of pregnant women after delivery. This study was performed to evaluate the efficacy of antiviral agents in preventing MTCT of HBV and maternal long-term outcomes. METHODS: The HBV-infected pregnant women treated with antiviral agents to prevent MTCT were retrospectively reviewed. Forty-one pregnant women who received telbivudine or tenofovir during late pregnancy (28-34 week) were analyzed. Hepatitis B virus surface antibody (HBsAb) positivity was tested in 43 infants after 7 months of birth. Eleven mothers were followed >1 year after delivery. RESULTS: The mean HBV DNA titer before antiviral therapy was 8.67 (6.60–9.49) log copies/mL, and the median age at delivery was 32 years (range, 22–40). Eleven patients were treated with tenofovir and 30 with telbivudine. The median duration was 57 days (range, 23–100), and the median HBV DNA titer at birth was 5.06 log copies/mL (range, 2.06–6.50). Antiviral treatments were associated with significant HBV DNA reduction (P 12 months, and an antiviral agent was administered. CONCLUSIONS: Antiviral treatment during late pregnancy effectively reduced MTCT. Long-term follow-up should be required in such cases. In addition, given that maternal biochemical flare occurred in 18% of mothers, re-administration of antiviral agents might be required.

Diagnosis of Liver Fibrosis With Wisteria floribunda Agglutinin-Positive Mac-2 Binding Protein (WFA-M2BP) Among Chronic Hepatitis B Patients

BACKGROUND: Wisteria floribunda agglutinin-positive Mac-2 binding protein (WFA-M2BP) is a protein with altered glycosylation that reacts with lectin, and was recently identified as a useful non-invasive biomarker for the diagnosis of liver fibrosis in patients with hepatitis C virus infection.This study aimed to evaluate the diagnostic efficacy of WFA-M2BP for liver fibrosis in the context of hepatitis B virus (HBV). METHODS: We enrolled 151 patients infected with HBV. Liver biopsy and elastography (Fibroscan) were performed during the initial visit. Fibrosis was graded according to the Knodell histologic activity index (F0–3). WFA-M2BP levels were determined with an automated immunoassay analyzer (M2BPGi, HISCL-5000, Sysmex, Japan). The diagnostic efficacy of WFA-M2BP was compared with those of various conventional or composite biomarkers, including enhanced liver fibrosis (ELF) score, Fibroscan, aspartate transaminase (AST)-to-platelet ratio index (APRI), and FIB-4, based on the area under the ROC curve (AUC) value. RESULTS: The majority of patients were at fibrosis stages F1 and F2. The F2 and F3 AUC values for WFA-M2BP were similar to those for FIB-4, APRI, ELF, and Fibroscan, although the latter showed the best diagnostic efficacy. The diagnostic accuracy of all tested biomarkers for F2 and F3 was 60–70%. In multivariate analysis, WFA-M2BP, ELF, and platelet count significantly predicted stage ≥F2, whereas only platelet count significantly predicted F3. CONCLUSIONS: WFA-M2BP can support a diagnosis of liver fibrosis with similar diagnostic efficacy to other biomarkers, and predicted liver fibrosis stage ≥2 among patients with chronic hepatitis B.

Interferon-free treatment for hepatitis C virus infection induces normalization of extrahepatic type I interferon signaling

BACKGROUND/AIMS: Hepatitis C virus (HCV) replicates in the peripheral blood mononuclear cells (PBMCs), leading to the production of type I interferons (IFNs). It is well known that the gene expression profile of PBMC is similar to that of the liver. The present study explored the dynamic gene expression profile of PBMCs collected from HCV-infected patients undergoing direct-acting antiviral (DAA) therapy. METHODS: A prospective cohort comprising 27 patients under DAA therapy was formed. Expression level of IFN-β and its downstream interferon-stimulated genes (ISGs) was measured in PBMCs before and after DAA treatment. Furthermore, immunoblotting was performed to identify the signaling molecules involved in the expression of ISGs. RESULTS: The pretreatment expression level of interferon-induced protein 44 (IFI44) and C-X-C motif chemokine ligand 10 (CXCL10) correlated with the pretreatment expression level of IFN-β. After DAA treatment, a significant decrease in the expression levels of IFN-β, IFI44, and CXCL10 was observed in the PBMCs. Furthermore, the pretreatment expression level of IFN-β and ISGs correlated with the level of signal transducer and activator of transcription 1 (STAT1) phosphorylation, and DAA treatment abrogated STAT1 phosphorylation. CONCLUSIONS: Pretreatment activation of IFN-β response is rapidly normalized after DAA treatment. The present study suggests that the decreased type I IFN response by the clearance of HCV might contribute to DAA-induced alleviation of extrahepatic manifestation of chronic HCV infection.

Transarterial Chemolipiodolization for Hepatocellular Carcinoma with Central Bile Duct Invasion Causing Conjugated Hyperbilirubinemia: Safety and Prognostic Factors for Survival

BACKGROUND/AIMS: The treatments and outcomes of hepatocellular carcinoma (HCC) with bile duct invasion are not well known. We aimed to confirm the safety of transarterial chemolipiodolization (TACL) and identify prognostic factors for patients with bile duct invasion treated with TACL. METHODS: Fifty patients with central bile duct invasion treated with TACL between 2005 and 2017 were enrolled. Patients were divided into three groups: hyperbilirubinemia (total bilirubin ≥2.5 mg/dL) with pre-TACL biliary drainage, hyperbilirubinemia without biliary drainage, and without hyperbilirubinemia. Tumor response to TACL, survival outcomes, length of hospitalization, adverse events using Common Terminology Criteria for Adverse Events (CTCAE), and factors affecting overall survival were compared. RESULTS: TACL-induced changes of mean CTCAE grades for albumin, alanine aminotransferase, creatinine, prothrombin time, and platelet were not significantly different among patients with or without initial hyperbilirubinemia. Serum bilirubin level was not significantly changed after TACL in all the three groups. Overall survival was not significantly different among the three groups (P=0.097). On multivariate analysis, alpha-fetoprotein < 400 ng/dL (hazard ratio [HR]=0.477, P=0.048) and highest total bilirubin level of < 2.5 mg/dL within one month after TACL (HR=0.335, P=0.004) were significantly associated with longer survival. CONCLUSIONS: TACL was a safe treatment for HCC patients with central bile duct invasion, irrespective of the presence of initial hyperbilirubinemia.

Reactivation of Hepatitis C Virus and Its Clinical Outcomes in Patients Treated with Systemic Chemotherapy or Immunosuppressive Therapy

BACKGROUND/AIMS: According to the results of several studies, the outcome of hepatitis C virus (HCV) reactivation is not as severe as the outcome of hepatitis B virus reactivation. The aim of this study was to evaluate the effect of pharmacological immunosuppression on HCV reactivation. METHODS: The medical records of patients who underwent systemic chemotherapy, corticosteroid therapy, or other immunosuppressive therapies between January 2008 and March 2015 were reviewed. Subsequently, 202 patients who were seropositive for the anti-HCV antibody were enrolled. Exclusion criteria were: unavailability of data on HCV RNA levels, a history of treatment for chronic hepatitis C, and the presence of liver diseases other than a chronic HCV infection. RESULTS: Among the 120 patients enrolled in this study, hepatitis was present in 46 patients (38%). None of the patients were diagnosed with severe hepatitis. Enhanced replication of HCV was noted in nine (27%) of the 33 patients who had data available on both basal and follow-up HCV RNA loads. Reappearance of the HCV RNA from an undetectable state did not occur after treatment. The cumulative rate of enhanced HCV replication was 23% at 1 year and 30% at 2 years. CONCLUSIONS: Although enhanced HCV replication is relatively common in HCV-infected patients treated with chemotherapy or immunosuppressive therapy, it does not lead to serious sequelae.

Immunoproteasome induction is suppressed in hepatitis C virus-infected cells in a protein kinase R-dependent manner

By changing the relative abundance of generated antigenic peptides through alterations in the proteolytic activity, interferon (IFN)-γ-induced immunoproteasomes influence the outcome of CD8⁺ cytotoxic T lymphocyte responses. In the present study, we investigated the effects of hepatitis C virus (HCV) infection on IFN-γ-induced immunoproteasome expression using a HCV infection cell culture system. We found that, although IFN-γ induced the transcriptional expression of mRNAs encoding the β1i/LMP2, β2i/MECL-1 and β5i/LMP7 immunoproteasome subunits, the formation of immunoproteasomes was significantly suppressed in HCV-infected cells. This finding indicated that immunoproteasome induction was impaired at the translational or posttranslational level by HCV infection. Gene silencing studies showed that the suppression of immunoproteasome induction is essentially dependent on protein kinase R (PKR). Indeed, the generation of a strictly immunoproteasome-dependent cytotoxic T lymphocyte epitope was impaired in in vitro processing experiments using isolated 20S proteasomes from HCV-infected cells and was restored by the silencing of PKR expression. In conclusion, our data point to a novel mechanism of immune regulation by HCV that affects the antigen-processing machinery through the PKR-mediated suppression of immunoproteasome induction in infected cells.

Immunogenicity of MenACWY-CRM in Korean Military Recruits: Influence of Tetanus-Diphtheria Toxoid Vaccination on the Vaccine Response to MenACWY-CRM

The quadrivalent meningococcal conjugate vaccine (MenACWY-CRM) has been introduced for military recruits in Korea since 2012. This study was performed to evaluate the immunogenicity of MenACWY-CRM in Korean military recruits. In addition, the influence of tetanus-diphtheria toxoids (Td) vaccination on the vaccine response to MenACWY-CRM was analyzed. A total of 75 military recruits were enrolled. Among them, 18 received a dose of MenACWY-CRM only (group 1), and 57 received Td three days before MenACWY-CRM immunization (group 2). The immunogenicity of MenACWY-CRM was compared between the two groups. The serum bactericidal activity with baby rabbit complement was measured before and three weeks after immunization against serogroups A, C, W-135, and Y. The geometric mean titers (GMTs) against four serogroups were significantly increased in both groups after immunization. Compared to group 2, group 1 exhibited significantly higher vaccine responses in several aspects: post-immune GMTs against serogroup A and C, seroresponse rates against serogroup A, and a fold increases of titers against serogroup A, C, and Y. MenACWY-CRM was immunogenic against all vaccine-serogroups in Korean military recruits. Vaccine response to MenACWY-CRM was influenced by Td administered three days earlier.

Immunogenicity of MenACWY-CRM in Korean Military Recruits: Influence of Tetanus-Diphtheria Toxoid Vaccination on the Vaccine Response to MenACWY-CRM

The quadrivalent meningococcal conjugate vaccine (MenACWY-CRM) has been introduced for military recruits in Korea since 2012. This study was performed to evaluate the immunogenicity of MenACWY-CRM in Korean military recruits. In addition, the influence of tetanus-diphtheria toxoids (Td) vaccination on the vaccine response to MenACWY-CRM was analyzed. A total of 75 military recruits were enrolled. Among them, 18 received a dose of MenACWY-CRM only (group 1), and 57 received Td three days before MenACWY-CRM immunization (group 2). The immunogenicity of MenACWY-CRM was compared between the two groups. The serum bactericidal activity with baby rabbit complement was measured before and three weeks after immunization against serogroups A, C, W-135, and Y. The geometric mean titers (GMTs) against four serogroups were significantly increased in both groups after immunization. Compared to group 2, group 1 exhibited significantly higher vaccine responses in several aspects: post-immune GMTs against serogroup A and C, seroresponse rates against serogroup A, and a fold increases of titers against serogroup A, C, and Y. MenACWY-CRM was immunogenic against all vaccine-serogroups in Korean military recruits. Vaccine response to MenACWY-CRM was influenced by Td administered three days earlier.